Separate from the “real-time clock” which keeps track of the time of day, the CPU clock sets the tempo for the processor and measures the transmission speed of electronic devices. The clock is used to synchronize data pulses between sender and receiver. A one megahertz clock manipulates a set number of bits one million times per second. In general, the higher the clock speed, the quicker data is processed. However, newer versions of software often require quicker computers just to maintain their overall processing speed.

The hertz is named in honor of Heinrich Hertz (1857–1894) who detected electromagnetic waves in 1883. One hertz is equal to the number of electromagnetic waves or cycles in a signal that is one cycle per second.